.div1 {
  background-color: #6699ff;
  width: 200px;
  height: 200px;
  position: absolute;
  margin: auto;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}

.box {
  position: relative;
  width: 500px;
  height: 500px;
  background-color: red;
}
